UNIVERSITY    OF    CALIFORNIA     AGRICULTURAL   EXPERIMENT  STATION 

*»«%■  ■  m^m,     **■     .«**•■#»..■*..-..  BENJ.    IDE    WHEELER,    PRESIDENT 

COLLEGE   OF  AGRICULTURE  THQMAS  FQRSYTH  hunt    Deanano  ,,_.„ 

BERKELEY  H.    E.  VAN    NORMAN,   Vice-Director   and   Dean 

University  Farm  Schooi 

CIRCULAR  No.  211 
April,' 1919 

SAVING  RAISINS  BY  SULFURING 

By  FKEDEKIC  T.  BIOLETTI  and  A.  E.  WAY 


An  improved  method  of  saving  raisins  in  rainy  weather  has  been 
tested  at  the  Kearney  Experiment  Vineyard  for  three  seasons,  two 
of  which  were  exceptionally  wet,  with  encouraging  results.  It  consists 
in  sulfuring  the  raisins  as  soon  as  they  are  stacked  after'  rain. 

Its  advantages  are :  1.  Even  in  the  wettest  and  most  unfavorable 
season  yet  experienced  in  Fresno  it  enables  the  grower  to  save  his  crop. 

2.  The  cost  of  stacking  is  much  reduced  because:  (a)  It  is  not 
necessary  to  stack  until  it  has  actually  rained.  Even  though  the  raisins 
are  thoroughly  wet  they  can  be  saved  and  the  useless  stacking  that  is 
forced  by  a  threat  of  rain  is  avoided.  (&)  Stacking  at  night  and  in 
haste  with  the  consequent  payment  of  an  excessive  rate  of  wages  is 
not  necessary.  A  few  hours  or  even  two  or  three  days  may  elapse 
before  stacking  without  great  harm.  Molding  does  not  commence  for 
some  time,  especially  if  the  weather  is  cold,  and  as  soon  as  the  raisins 
are  sulfured  they  are  safe,  (c)  The  wet  sulfured  raisins  may  remain 
in  the  stack  for  many  days  without  injury.  It  is  not  necessary,  there- 
fore, to  be  in  a  hurry  to  unstack  them.  It  is  safe  to  wait  a  week 
or  more  if  necessary  until  the  weather  is  definitely  settled. 

The  Sulfuring  Hood. — In  order  to  apply  this  method,  the  grower 
must  be  furnished  with  a  hood  to  cover  the  stacks  and  to  confine  the 
fumes  of  the  burning  sulfur  until  they  have  accomplished  their  object. 
The  hood  described  here  was  made  by  Mr.  A.  E.  Way,  of  the  Viticul- 
tural  Division,  and  Mr.  W.  A.  MacCutcheon,  Assistant  Farm  Advisor 
of  Fresno.  It  is  a  modification  of  the  hoods  which  have  been  used  by 
Mr.  Way  successfully  for  three  years. 

The  lowest  photograph  in  fig.  1  shows  the  completed  hood  and  the 
others,  the  frame  in  process  of  construction.  Fig.  2  shows  the  details 
of  construction  of  this  frame. 

The  hood  made  from  these  specifications  will  cover  about  twenty- 
six  trays  in  two  stacks.  It  is  light  and  easily  handled  by  two  men. 
This  size  was  adopted  as  the  most  convenient  under  average  conditions. 
If  it  were  larger  it  would  not  only  be  more  difficult  to  handle,  and 
therefore  more  subject  to  injury,  but  it  would  necessitate  carrying  the 
trays  a  long  distance  in  order  to  make  a  stack  large  enough  to  fill  it. 

The  hoods  should  be  used  in  sets  or  outfits  and  four  men  are  needed 
for  each  set.  Two  men  first  collect  the  trays  and  pile  them  in  two 
stacks.  The  other  two  then  carry  a  hood  to  these  stacks,  place  it  over 
them,  and  then  place  a  pan  with  about  half  a  pound  of  sulfur  between 


Fig.  1. — Sulfuring  hood  in  process  of  construction. 


Fig.  2. — Wooden  frame  of  sulfuring  hood. 


Material  and  Cost 


amber  for  frame: 

2  pieces  1"  X  3"  14'  long... 

$  .30 

2  pieces  1"  X  3"  12'  long... 

.25 

2  pieces  1"  X  3"  10'  long... 

.22 

2  pieces  1"  X  2"  12'  long... 

.15 

27  cleats  %"  X  %"  3'  long .. 

.23 

$1.15 


Covering  of  frame: 

26  ft.  double-ply  bldg.  paper  $  .42 
Nails,  184  2%",  48  2",  162 

1%"    - 13 

Labor : 

2  men  2  hours  at  40  cents.—     1.60 

$2.15 
Total $3.30 


Specifications  for  Cutting  the  Material 
2  pieces  1"  X  3"  10',  bottom  strips,  extending  2'  for  handles. 

piece  1"  X  3"  12',  cut  2  pieces  6'  (top  sides). 

piece  1"  X  3"  14',  cut  4  pieces  3'  414"    (ends). 

piece  1"  X  3"  14',  cut  4  pieces  3'  3%"   (end  uprights). 

piece  1"  X  3"  12',  cut  4  pieces  2'  9%"   (side  uprights). 

piece  1"  X  2"  12',  cut  3  pieces  3'  6"    (tops). 

piece  1"  X  2"  12',  cut  4  pieces  2'  9"   (tops). 
2  pieces  building  paper,  6'  long  X   3'  wide   (sides). 
2  pieces  building  paper,  3'  6"  long   X   3'  wide  (ends). 
2  pieces  building  paper,  3'  6"  long  X   3'  wide  (top). 
Cleats  nailed  along  edges  of  paper. 


(1) 
(2) 
(3) 
(4) 
(5) 
(6) 
(7) 


the  two  stacks.  They  then  light  the  sulfur  and  immediately  shovel  a 
little  soil  around  the  base  of  the  hood  to  make  it  air  tight.  These 
operations  take  about  three  minutes,  and  by  this  time  the  sulfur  has 
done  its  work  under  another  hood.  This  hood  is  then  removed  and 
carried  to  another  pair  of  stacks  and  the  operations  repeated.  As  it 
takes  just  about  four  minutes  to  assemble  and  stack  twenty-six  trays 
where  the  crop  is  of  average  size  the  operations  are  continuous  and  no 
time  is  lost. 

In  making  the  two  stacks  they  must  be  placed  at  exactly  the  proper 
distance  apart,  parallel  to  each  other  and  vertical.  Otherwise,  time 
will  be  lost  in  moving  stacks  in  order  to  put  the  hood  in  place,  and 
there  is  danger  of  breaking  the  hood  in  placing  it  over  crooked  stacks. 

The  correct  placing  of  the  stacks  is  much  facilitated  by  using  a 
guide.  A  suitable  guide  can  be  made  from  a  3-inch  batten  12  feet  long 
cut  into  one  piece  6  feet  4  inches  long,  two  pieces  18  eighteen  inches 
long,  and  two  pieces  1  foot  4  inches  long.  The  long  piece  is  placed  on 
edge  and  the  18-inch  pieces  nailed  to  it  at  right  angles  six  inches  from 
each  end.  The  shortest  pieces  are  then  used  as  braces  to  keep  the  guide 
square. 


5' 4* 


i 


Fig.  3. — Guide  for  making  stacks. 

Fig.  3  shows  the  method  of  stacking  with  this  guide.  The  guide 
is  placed  on  the  ground  where  the  stacks  are  to  be  made  and  a  tray 
placed  in  each  angle.  Twelve  or  less  trays  are  then  placed  on  each  of 
these  bottom  trays  and  the  stacks  when  completed  will  be  in  exactly 
the  correct  position  to  be  covered  by  the  hood  and  to  allow  space 
between  for  the  sulfur  pan. 

The  cost  of  the  operations  per  ton  can  be  estimated  from  the  results 
of  tests  at  the  Kearney  Experiment  Vineyard,  as  follows : 

Stacking,  sulfuring,  and  unstacking  once $2.56 

Sulfur,  at  $4  per  100  pounds 22 

Amortization  of  cost  of  hoods,  at  20  per  cent 23 

Total    $3.01 

The  cost  of  the  ordinary  stacking  per  ton,  based  on  results  in  1918, 
is  about  as  follows  : 

Stacking  once  $  .80 

Unstacking   once   70 

Stacking  and  unstacking,  second  time 1.40 

Total    $2.90 

These  estimates  are  based  on  a  wage  of  $4  per  day  of  eight  hours 
and  the  use  of  eight  hoods  and  four  men  for  each  outfit. 

The  number  of  hoods  necessary  for  each  outfit  depends  on  the  time 
to  which  the  grapes  must  be  subjected  to  the  sulfur  fumes.  With  two 
hoods,  this  would  be  only  five  minutes ;  with  eight  hoods,  it  would  be 
thirty-five  minutes.  The  time  necessary  has  not  been  determined,  but 
it  is  probably  less  than  thirty-five  minutes  and  more  than  five. 

As,  in  ordinary  weather,  the  wet  raisins  would  not  commence  to 
mold  until  after  three  days,  a  single  outfit  would  be  sufficient  for  a 
crop  of  about  twenty-five  tons  or  say  twenty  acres. 

The  cost  when  the  hoods  were  used  would  be  about  3  per  cent  of 
the  value  of  the  crop,  or  about  50  per  cent  greater  than  two  ordinary 
stackings.  As  they  would  make  some  stackings  unnecessary,  as  they 
would  avoid  the  necessity  of  paying  panic  wages,  and  as  they  would 
insure  the  saving  of  the  crop,  there  would  be  a  considerable  net  gain 
from  their  use. 


